PROS

Indoor construction. Assembly is independent of weather which often leads to cost overruns on site-built dwellings.

The speed of having a home built: these new homes can be constructed in a fraction of the time it takes to build a home "on-site".

Favorable pricing from suppliers. Large-scale manufacturers can effectively bargain with suppliers for discounts on materials.

Low waste. With the same plans being constantly built, the manufacturer has records of exactly what quantities of materials are needed for a given job. While waste from a site-built dwelling may typically fill several large dumpsters, waste from a modular dwelling is much less. The ability to have the foundation built while the house is being built in the factory.

Built to the same building code as on-site-built houses.

The on-site assembly process takes only hours or days, rather than weeks or months as is typical with site-built housing. Once assembled, modular buildings are essentially indistinguishable from typical site-built homes. While mobile manufactured homes often decrease in value over time, a well-built modular should have the same longevity as its site-built counterpart, increasing in value over time.[Citation: http://en.wikipedia.org/wiki/Modular_home]